The O-Zone: Today's Lesson: Well, Ozone Again

November 27, 2002

This column will discuss well ozone water treatment for residential, commercial and industrial applications. Well ozone water treatment systems for the removal of

  • Iron/iron bacteria,
  • Sulfur/sulfur bacteria,
  • Manganese,
  • Bacteria, and
  • Taste/odor.

Iron, sulfur and manganese are the easiest water problems to eliminate when using an ozone system. This, of course, is made possible by the oxidation power of ozone. The oxidation process will take place, and contaminate elimination will occur if the system is sized properly.

The main factors to consider are the big three.

  • What is the water quality?
  • How much flow (gpm)?
  • How much used (gpd)?

You will notice I use the words "ozone systems," not just "ozone." The reason is that ozone is merely a gas that accomplishes the oxidation process. Oxidation is the first step of three that must be followed in order to be successful.

The ozone process works in three simple steps.

  • Ozone injection/oxidation. Ozone is triatomic oxygen (O3), which has very high oxidizing power. It is a gas produced from air and high voltage electricity. The injection of the ozone into the water produces tiny ozone bubbles, which saturate every drop of water. At this point, oxidation of iron, sulphur and manganese is immediate. The ozone unit (ozonator) is the device that produces the ozone. Its design should be simple, waterproof and short circuit protected by resettable breaker field service and should feature a plastic/non-corrosive housing and stainless steel ozone generator construction. Ozone must be injected into the water after it is produced. There are two methods most commonly used.
  • Ozone Pump - A positive displacement injector that pumps the ozone gas into the water similar to a chemical feed pump for chlorine. There is no restriction of flow or pressure and it achieves the greatest volume of ozone injection. This is an important factor when dealing with iron and sulfurs greater than 3 ppm.
  • Venturi - A device that restricts flow and pressure in order to produce a vacuum. This vacuum device sucks the ozone gas into the water. Improper sizing will result in insufficient ozone suction, which will cause insufficient oxidation. Air dryers are options that reduce the maintenance of the ozone equipment. Air dryers remove all of the humidity and moisture from the air prior to the ozonator. The air is dried to a minimum of –40° F dew point (absolutely dry/no moisture). Dry air increases ozone production and can extend service life of the ozone generators and ozone pump.
  • Aeration. The elimination (off gassing or venting) of the ozone and other gases/odors, such as sulfur occurs by an ozone stripping action. As water flows down the off gas tank, ozonated water rises and strips any gas in the incoming water.
  • Filtration. The final step for removing the oxidized material is filtration. The media used should have low water waste (backwash), high service flow, high removal capacity and require no chemicals during regeneration. Mechanical filtration is all that is necessary if proper oxidation has been achieved.

 

Ozone System vs. Chlorination Systems

The main advantage for the consumer using ozone over chlorine is the absence of hazardous chlorine byproducts, storage of hazardous chemicals, absence of chemical odors, and lack of constant replenishment of the chlorine feeder. Trying to oxidize/kill iron bacteria, sulfur bacteria or manganese (as well as any microorganisms) with chlorine is difficult and requires extreme amounts of free chlorine. This leads to dramatically increase ongoing costs as well as a highly toxic water value.

Ozone Systems vs. Air Injection Systems

Air injection is fraught with difficulties. While it is an inexpensive treatment method, it cannot be used on high iron and sulfur amounts and when iron or sulfur bacteria is present.

Iron and sulfur bacteria will grow when in the presence of air. This leads to pipe, media and equipment clogging. Manganese is more difficult and resistant to air oxidation.

Safety is another issue. How can you determine that the air you are injecting into your customers water is safe? You cannot when using a simple air injector system. Anything in the air (dust, dirt, mold, bacteria, odors, etc.) around the injector gets sucked or pumped into the water. Ozone is a sterilizer and it will kill any air borne microbes prior to being injected into the water.

  • The main advantage for the dealer when using an ozone system is
  • Reduced service calls,
  • Complete and immediate oxidation,
  • Complete and immediate removal of the iron, sulfur and manganese,
  • Increased profitability, and
  • Low or no environmental impact.

To review the overall process: Ozone creates larger particles of iron, sulfur, and manganese by means of oxidation. The larger particles become insoluble (separated from the water) and are easily filtered. The off gassing releases the excess ozone, air and odors. Filtration is the last step necessary for removing the oxidized particles.

Next month's column will discuss the fine points of selling ozone systems.

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